Matthew Aliota, Department of Pathobiological Sciences, School of Veterinary Medicine, University of Wisconsin-Madison

Abstract: Like any population of organisms, a virus population interacts with, reacts to, influences, and is influenced by the environment it inhabits. Starting from a single genome, RNA viruses are able to generate high levels of genetic plasticity through large population sizes, rapid replication kinetics, and high mutation rates resulting from error-prone polymerases. Ultimately, error-prone replication allows the virus to explore sequence space to gain adaptability and accumulate potentially advantageous mutations; therefore, the generation of more genetic variants per unit time facilitates adaptive fitness advantages for an RNA virus. Understanding the mechanisms that mediate host restriction among arboviruses and assessing the evolutionary potential of host-restricted members of certain genera to switch hosts will help fill the gaps in our understanding of how new vector-borne pathogens evolve and become established in new host populations. Likewise, understanding the processes by which arboviruses acquire new phenotypes in the face of complex selective environments (e.g., a partially resistant vector population) is critically important for the prediction, prevention, and control of emerging arboviral diseases. To provide a more comprehensive understanding of these unique and complex relationships, I have developed two tractable, laboratory models to provide a pragmatic assessment of the impact of host switching and host resistance on arbovirus evolution. Future experiments will address why certain flaviviruses infect mosquitoes and vertebrates while others infect mosquitoes or vertebrates exclusively; and if an arbovirus can evolve to overcome a novel vector control strategy relying on the deployment of Wolbachia-infected Aedes aegypti.